U.S. patent application number 15/613618 was filed with the patent office on 2018-01-04 for near synchronous distributed hydraulic motor driven actuation system.
The applicant listed for this patent is Parker-Hannifin Corporation. Invention is credited to Eric Alexander Polcuch.
Application Number | 20180002028 15/613618 |
Document ID | / |
Family ID | 60806505 |
Filed Date | 2018-01-04 |
United States Patent
Application |
20180002028 |
Kind Code |
A1 |
Polcuch; Eric Alexander |
January 4, 2018 |
NEAR SYNCHRONOUS DISTRIBUTED HYDRAULIC MOTOR DRIVEN ACTUATION
SYSTEM
Abstract
A control system may be used to control actuators that actuate
movement of flight control surfaces of an aircraft. Each actuator
is couplable to a flight control surface and includes a motion
control assembly having a hydraulic motor and a drive path from the
hydraulic motor to the flight control surface. Each hydraulic motor
includes an extend port and a retract port. The system includes a
hydraulic control module fluidly connected to the extend port and
the retract port of each hydraulic motor and a controller operable
to output hydraulic power from the hydraulic control module to the
motion control assembly to actuate movement of the flight control
surfaces. The controller is configured to identify an actuator that
positionally leads the other actuators and reduce hydraulic power
to the motion control assembly assigned to such actuator.
Inventors: |
Polcuch; Eric Alexander;
(Mission Viejo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Parker-Hannifin Corporation |
Cleveland |
OH |
US |
|
|
Family ID: |
60806505 |
Appl. No.: |
15/613618 |
Filed: |
June 5, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62356037 |
Jun 29, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64C 13/505 20180101;
B64C 13/36 20130101; B64C 13/504 20180101; B64C 9/22 20130101; B64C
9/16 20130101; B64C 9/323 20130101 |
International
Class: |
B64D 31/12 20060101
B64D031/12; F16H 61/04 20060101 F16H061/04; F16H 61/06 20060101
F16H061/06 |
Claims
1. A control system for controlling a plurality of actuators, the
control system comprising: a plurality of actuators for actuating
movement of one or more adjustable components of an aircraft,
wherein each actuator has a first end couplable to a structure of
the aircraft and a second end couplable to one of the one or more
adjustable components, each actuator including a motion control
assembly having a hydraulic motor and a drive path from the
hydraulic motor to the one or more adjustable components, each
hydraulic motor having an extend port and a retract port wherein
the one or more adjustable components are configured to move along
a respective drive path; a hydraulic control module fluidly
connected to the extend port and the retract port of each hydraulic
motor; and a controller operable to output hydraulic power from the
hydraulic control module to each motion control assembly to actuate
movement of the one or more adjustable components.
2. The control system of claim 1, wherein the controller is
configured to identify an actuator of the plurality of actuators
that positionally leads other actuators of the plurality of
actuators, and reduce hydraulic power to the motion control
assembly assigned to the actuator that positionally leads the other
actuators.
3. The control system of claim 1, wherein the hydraulic control
module includes at least one directional control valve that reduces
or bypasses hydraulic power to at least one actuator of the
plurality of actuators.
4. The control system of claim 3, wherein the at least one
directional control valve is in fluid communication between the
extend port of a first actuator and the retract port of a second
actuator.
5. The control system of claim 3, wherein the at least one
directional control valve includes a plurality of directional
control valves, wherein each of the plurality of directional
control valves corresponds to one of the plurality of
actuators.
6. The control system of claim 3, wherein the at least one
directional control valve is a fine control solenoid valve.
7. The control system of claim 3, wherein the hydraulic control
module includes at least one pilot operated load limiting valve for
blocking flow to one of the plurality of actuators when supply
pressure exceeds a predetermined value.
8. The control system of claim 7, wherein the at least one pilot
operated load limiting valve is a bi-directional valve.
9. The control system of claim 1, wherein the hydraulic control
module includes at least one electro-hydraulic servo valve.
10. The control system of claim 1, wherein the hydraulic motor
includes a hydraulically operated brake.
11. The control system of claim 1, wherein each of the plurality of
actuators includes an acme, ball, or roller screw type linear
actuator.
12. The control system of claim 1, wherein each of the plurality of
actuators includes a gear-driven rotary actuator.
13. The control system of claim 1, wherein at least one of the
plurality of actuators includes a mechanical overload protection
device, the mechanical overload protection device being a slip
clutch, a torque activated overload brake, or a load activated
overload brake.
14. The control system of claim 1, wherein at least one of the
plurality of actuators includes a no-back mechanism for preventing
an applied load from backdriving the at least one of the plurality
of actuators.
15. The control system according to claim 1, wherein the controller
includes a first controller that outputs controlled hydraulic drive
power to a first set of actuators for actuating movement of a first
set of components and a second controller that outputs controlled
hydraulic drive power to a second set of actuators for actuating
movement of a second set of components.
16. The control system according to claim 15, wherein the first set
of components and the second set of components includes at least
one of a flap, a slat, a spoiler, an aileron, and an elevator.
17. The control system according to claim 15, wherein the first set
of components includes a left outboard flap and a right outboard
flap, and the second set of components includes a left inboard flap
and a right inboard flap.
18. A method for controlling a plurality of actuators for actuating
movement of one or more adjustable components of an aircraft, the
aircraft including a plurality of actuators for actuating movement
of one or more adjustable components, wherein each actuator has a
first end couplable to a structure of the aircraft and a second end
couplable to one of the one or more adjustable components and each
actuator additionally includes a motion control assembly having a
hydraulic motor and a drive path from the hydraulic motor to the
one or more adjustable components, wherein the one or more
components is configured to move along a respective drive path, the
method comprising: supplying hydraulic drive power from a hydraulic
power module through a hydraulic circuit to the motion control
assembly for each actuator to actuate movement of the one or more
adjustable components; identifying an actuator of the plurality of
actuators that positionally leads other actuators of the plurality
of actuators; and reducing hydraulic power to the motion control
assembly assigned to the actuator that positionally leads the other
actuators.
19. The method according to claim 18, wherein the aircraft includes
one or more position feedback devices operatively coupled to
respective ones of the one or more adjustable components, the
method further comprising: identifying the actuator that
positionally leads the other actuators based on a comparison of the
position data provided by the respective one or more position
feedback devices.
20. The method according to claim 18, further comprising
controlling the output of each of the actuators by maintaining near
synchronous output signals over an applied load range within a
volumetric efficiency of the motion control assembly over an
operating range between a no-load and an operating point maximum
load.
Description
FIELD OF INVENTION
[0001] The present invention relates to a hydro-mechanical
actuation drive system requiring the synchronous (or near
synchronous) operation of multiple individual actuators.
BACKGROUND
[0002] Modern thin wing aircraft designs are aimed at optimizing
fuel economy. Due to the thin wing design, the area along the spars
of the wings may be congested such that routing of mechanical drive
shafts, such as torque tubes, between the central power drive unit
and actuators and between actuators may be difficult.
[0003] Prior actuation systems may eliminate torque tube routes by
providing individual servo-controlled electric actuators at each
actuation station such that each station may use one or more motor
controllers with associated motor commutation signals and loop
closures. Using a multiple controller system may have complex
wiring for the controllers and require more components than in
other actuation systems. Thus, the prior actuation system may have
disadvantages with regards to system reliability, the overall
weight of the system aboard the aircraft, the envelope of the
aircraft, and the ability to perform maintenance on the system.
SUMMARY OF INVENTION
[0004] The present invention is directed towards a hydraulic motor
driven actuation system that enables torque tube routes to be
eliminated from the actuation system. The present invention
provides hydraulic power systems and low powered electronics for
position sensing, outer loop solenoid control, or electro-hydraulic
servo valve control. The hydraulic motor driven actuation system
may be advantageous in that the system may use a common hydraulic
power source that drives multiple actuators and provides for
synchronous or near-synchronous motion of the actuators. The
actuation system has the ability to fit into thin wings and has a
reduced component count, such that the system is cost-efficient to
manufacture and contributes less weight to the aircraft.
[0005] According to an aspect of the invention, a control system
for controlling a plurality of actuators may include a plurality of
actuators for actuating movement of one or more adjustable
components of an aircraft, and each actuator may have a first end
couplable to a structure of the aircraft and a second end couplable
to one of the one or more adjustable components. Each actuator may
include a motion control assembly having a hydraulic motor and a
drive path from the hydraulic motor to the one or more adjustable
components. Each hydraulic motor may have an extend port and a
retract port and the one or more adjustable components may be
configured to move along a respective drive path. The control
system may include a hydraulic control module fluidly connected to
the extend port and the retract port of each hydraulic motor and a
controller operable to output hydraulic power from the hydraulic
control module to each motion control assembly to actuate movement
of the one or more adjustable components.
[0006] According to another aspect of the invention, a method for
controlling a plurality of actuators for actuating movement of one
or more adjustable components of an aircraft may be implemented in
the aircraft that includes a plurality of actuators for actuating
movement of one or more adjustable components. Each actuator may
have a first end couplable to a structure of the aircraft and a
second end couplable to one of the one or more adjustable
components and each actuator additionally may include a motion
control assembly having a hydraulic motor and a drive path from the
hydraulic motor to the one or more adjustable components. The one
or more components may be configured to move along a respective
drive path. The method may include supplying hydraulic drive power
from a hydraulic power module through a hydraulic circuit to the
motion control assembly for each actuator to actuate movement of
the one or more adjustable components, identifying an actuator of
the plurality of actuators that positionally leads other actuators
of the plurality of actuators, and reducing hydraulic power to the
motion control assembly assigned to the actuator that positionally
leads the other actuators.
[0007] Other systems, devices, methods, features, and advantages of
the present invention will be or become apparent to one having
ordinary skill in the art upon examination of the following
drawings and detailed description. It is intended that all such
additional systems, methods, features, and advantages be included
within this description, be within the scope of the present
invention, and be protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic drawing showing an exemplary aircraft
in accordance with aspects of the present invention.
[0009] FIG. 2A is a schematic drawing showing a first exemplary
embodiment of an actuation system for flight control surfaces of
the aircraft of FIG. 1.
[0010] FIG. 2B is a schematic drawing showing a second exemplary
embodiment of an actuation system for flight control surfaces of
the aircraft of FIG. 1.
[0011] FIG. 3A is a schematic drawing showing the actuation system
for actuation of hydro-mechanical actuators associated with a
trailing edge flap of the aircraft of FIG. 1.
[0012] FIG. 3B is a schematic drawing showing the actuation system
for actuation of hydro-mechanical actuators associated with a
leading edge flap of the aircraft of FIG. 1.
[0013] FIG. 4A is a schematic drawing showing a first exemplary
embodiment of an actuator for use in the actuation system of any of
FIGS. 2A-3B.
[0014] FIG. 4B is a schematic drawing showing a second exemplary
embodiment of an actuator for use in the actuation system of any of
FIGS. 2A-3B.
[0015] FIG. 4C is a schematic drawing showing a third exemplary
embodiment of an actuator for use in the actuation system of any of
FIGS. 2A-3B.
[0016] FIG. 5A is a schematic drawing showing a first exemplary
embodiment of a hydraulic control module for actuating a plurality
of actuators.
[0017] FIG. 5B is a schematic drawing showing a second exemplary
embodiment of a hydraulic control module for actuating a plurality
of actuators.
[0018] FIG. 5C is a schematic drawing showing a third exemplary
embodiment of a hydraulic control module for actuating a plurality
of actuators.
[0019] FIG. 5D is a schematic drawing showing a fourth exemplary
embodiment of a hydraulic control module for actuating a plurality
of actuators.
[0020] FIG. 5E is a schematic drawing showing a fifth exemplary
embodiment of a hydraulic control module for actuating a plurality
of actuators.
[0021] FIG. 5F is a schematic drawing showing a sixth exemplary
embodiment of a hydraulic control module for actuating a plurality
of actuators.
[0022] FIG. 6 is a schematic drawing showing a portion of a
hydraulic control module for controlling a single actuator.
[0023] FIG. 7 is a block diagram illustrating an exemplary method
for controlling a plurality of actuators.
[0024] FIG. 8 is a schematic drawing showing an exemplary
controller for executing the method of FIG. 7.
DETAILED DESCRIPTION
[0025] Aspects of the present invention relate to a distributed
hydro-mechanical actuation system that includes multiple
hydro-mechanical actuators intended to operate together in a
synchronous (or near synchronous) manner. Each individual actuator
may be powered by one or more hydraulic motors that are configured
to have a high volumetric efficiency with a low velocity loss
relative to the flow of hydraulic fluid. The group of actuators may
be controlled from a single hydraulic control module that includes
a pressure compensated flow control valve and a directional control
valve or an electro-hydraulic servo valve type of open loop control
in which the hydraulic flow rate is controlled to assure that the
motors operate at a predetermined speed. The output of the
actuators is maintained near synchronous over the applied load
range within a volumetric efficiency (e.g. internal leakage)
between motors over the operating range between a no-load and an
operating point maximum load. The group of actuators may be
re-synchronized every retract cycle by driving into calibrated
retract stops at a controlled speed and torque capability.
[0026] The hydro-mechanical actuation system as described herein
replaces a traditional actuator and torque tube type of actuation
system that is typical on most modern aircraft high lift systems.
Using the hydro-mechanical actuation system may eliminate a
configuration in which torque tubes and drive members are fed along
the wing spar.
[0027] Referring now to FIG. 1, a schematic diagram of a portion of
an exemplary aircraft and an exemplary flight control surface
actuation system is shown. In the illustrated embodiment, the
aircraft 10 may include a pair of elevators 12, a rudder 14, and a
pair of ailerons 16, which are the primary flight control surfaces,
and a plurality of flaps 18, slats 20, and spoilers 22, which are
the secondary flight control surfaces. The primary flight control
surfaces 12-16 may control aircraft movements about the aircraft
pitch, yaw, and roll axes. Specifically, elevators 12 may be used
to control aircraft movement about the pitch axis, the rudder 14
may be used to control aircraft movement about the yaw axis, and
the ailerons 16 may be used to control aircraft movement about the
roll axis. The aircraft movement about the yaw axis may also be
achieved either by banking the aircraft or by varying the thrust
levels from the engines on opposing sides of the aircraft 10.
[0028] The secondary control surfaces 18-22 may influence the lift
and drag of the aircraft 10. For example, during aircraft take-off
and landing operations, when increased lift is desirable, the flaps
18 and slats 20 may be moved from retracted positions to extended
positions. In the extended position, the flaps 18 increase both
lift and drag, and enable the aircraft 10 to descend more steeply
for a given airspeed, and also enable the aircraft 10 to get
airborne over a shorter distance. The slats 20, in the extended
position, may increase lift and allow for higher angles of attack
without aerodynamic stall of the wing, and are typically used in
conjunction with the flaps 18. The spoilers 22, on the other hand,
may reduce lift and when moved from retracted positions to extended
positions, which is typically done during aircraft landing
operations, and may be used as air brakes to assist in slowing the
aircraft 10.
[0029] Referring in addition to FIGS. 2A and 2B, the flight control
surfaces 18a, 18b, 18c, 18d may be moved between the retracted and
extended positions via a flight control surface actuation system
30. The flight control surface actuation system 30 is exemplary in
nature and not intended to limit the scope of the present
invention. The flight control surface actuation system 30 includes
one or more actuator controllers 32, 34, such as remote electronic
units (REUs) and a plurality of secondary flight control surface
hydro-mechanical actuator assemblies 36a, 36b, 36c, 36d, 36e, 36f,
36g, 36h. Each actuator controller 32, 34 is configured to control
operation of a plurality of flight control surfaces via a
corresponding hydraulic control module 32a, 34a, a transfer valve
35, and one or more connected hydraulic lines 37 that are in
communication with hydraulic motors of each of the hydro-mechanical
actuator assemblies 36a, 36b, 36c, 36d, 36e, 36f, 36g, 36h.
Furthermore, it will be appreciated that the number of actuator
controllers 32, 34 may vary. For simplicity purposes, the flight
control surface actuation system 30 shown in FIG. 2A includes a
dual channel system that is operable to control more than one
hydro-mechanical actuator in synchronous and/or near synchronous
manner through the hydraulic lines 37 and the transfer valve 35. As
used herein, the term "synchronous" and "near synchronous" mean
that some difference in actuator position may occur while providing
common controlled power to multiple actuators at the same time, but
the performance effect on the aircraft is insignificant.
[0030] The actuation system 30 and hydraulic control modules 32a,
34a may be implemented according to any one of numerous operational
configurations. For example, the system 30 could be configured such
that one of the hydraulic control modules 32a, 34a is active and
the other control module 32a, 34a is inactive (or standby) mode,
which may be used for redundancy purposes. Alternatively, the
system 30 may be configured such that both hydraulic control
modules 32a, 34a are active and controlling all, or selected ones,
of the flight control surface actuator assembly 36 (or as shown in
FIGS. 2A and 2B, the actuator assemblies 36a, 36b, 36c, 36d, 36e,
36f, 36g, 36h) to which they are coupled through the hydraulic
lines 35. Furthermore, while FIG. 2A illustrates a system with
redundant motors and controllers other systems and variations may
be used as would be appreciated by one have ordinary skill in the
art. For example, a simplex system of a single controller driving a
single motor on each of a plurality of actuators, as well as other
combinations of simplex and redundant system may be used in
accordance with aspects of the present invention. No matter the
specific configuration, each controller 32, 34 when active,
receives flight control surface position commands from one or more
non-illustrated external systems, such as a flight control computer
or pilot controls, for example. In response to the flight control
surface position commands, the active controllers and corresponding
hydraulic control modules may supply hydraulic fluid to drive the
hydraulic motors via hydraulic lines 37 that causes the flight
control surface actuator assemblies 36a, 36b, 36c, 36d, 36e, 36f,
36g, 36h to move the appropriate flight control surfaces 18-22
(FIG. 1) to the commanded flight control surface position in a
synchronous and/or near synchronous manner. The controller and the
corresponding hydraulic control module may also be configured to
control the fluid supply to the hydraulic motors to stop the
actuators at the desired position synchronously or near
synchronously.
[0031] The controllers 32, 34 may also receive monitor signals that
are representative of flight control surface actuator assembly 36,
38 operability. The controllers 32, 34, based on these monitor
signals, determine the operability of the flight control surface
actuator assembly 36. If one or both controllers 32, 34 determine
that a secondary flight control surface actuator assembly 36 is
partially inoperable, it may automatically compensate, if
necessary, the remaining active actuator(s) electric motor drive
power to compensate for that actuator assembly 36 for the partial
inoperability. It will be appreciated that the monitor signals that
the controllers 32, 34 receive may be supplied directly from the
flight control surface actuator assemblies 36, or from other
systems and components such as, for example, position sensors 40
(e.g., a linear variable differential transformer or other sensor),
which are coupled to the aircraft 10 and the flight control surface
to determine a position of the flight control surface. This
position information is used by the controller to determine when to
drive the actuators to stop, for example.
[0032] As further illustrated in FIG. 2A, the hydraulic control
modules 32a, 34a may be coupled to a left outboard flap 18a, a left
inboard flap 18b, a right inboard flap 18c, and a right outboard
flap 18d through hydraulic lines 37, such that in the event that
one of the hydraulic control modules 32a, 34a fails or one of the
controls 32, 34 fails, the actuation system 30 may still be
operable. For example, the hydraulic control module 32a may be a
primary controller and the hydraulic control module 34a may be a
redundant controller, for example. The hydraulic control modules
32a, 34b, when active, may supply hydraulic fluid to the hydraulic
motor that cause the secondary flight control surface actuator
assemblies 36 to move the appropriate flight control surface (e.g.,
flaps 18a-d) to the commanded flight control surface in a
synchronous and/or near synchronous manner. Thus, the present
system provides control of more than one control surface using a
dual channel configuration that may accommodate for the failure of
a controller, a hydraulic control module, or a sensor.
[0033] As illustrated in FIG. 2B, in another exemplary embodiment
of the actuation system 30', the system may be configured as a
simple dual channel split system. The controller 32 and hydraulic
control module 32a may be coupled to the outboard flaps 18a, 18d
through hydraulic lines 35a and the controller 34 may be coupled to
the inboard flaps 18b, 18c through hydraulic lines 35b. One of the
controllers 32, 34 may be a primary controller and the other
controller may be a redundant controller, for example. The
controllers 32, 34 and hydraulic control modules 32a, 34a may
supply hydraulic fluid to the hydraulic motors that cause the
secondary flight control surface actuator assemblies 36 to move the
appropriate flight control surface to the commanded flight control
surface in a synchronous and/or near synchronous manner. For
example, the controller 32 may control operation of outboard flaps
18a, 18d and the controller 34 may control operation of inboard
flaps 18b, 18c. Thus, the present system provides control of more
than one control surface with a single controller through the
hydraulic lines. In contrast to the actuation system shown in FIG.
2A, the actuation system 30' shown in FIG. 2B may be operable
without using a transfer valve.
[0034] The flight control surface actuation system 30 (or 30') may
also be implemented using various numbers and types of flight
control surface actuator assemblies 36, 38. In addition, the number
and type of flight control surface actuator assemblies 36, 38 per
control surface 12-22 may be varied. In the depicted embodiment,
the system 30 is configured such that a pair of redundant actuator
assemblies 36 are coupled to each of the secondary flight control
surfaces 18-22, and a single, redundant actuator assembly 38 is
coupled to each of the primary flight control surfaces 12-16. It is
noted that the embodiments depicted are merely exemplary, and that
the flight control surface actuation system 30 (or 30') could be
implemented in any one of numerous alternative configurations. For
example, the system 30 could be configured such that two or more
non-redundant actuator assemblies 36 are coupled to each, or
selected ones, of the secondary flight control surfaces 18-22 (FIG.
1). The system 30 could also be configured such that one or more
redundant actuator assemblies are coupled to one or more of the
secondary flight control surfaces 18-22, in addition to, or instead
of, the single non-redundant actuator assemblies.
[0035] FIG. 3A shows a traditional trailing edge flap system 20'
that may implement the actuation system according to the present
invention. FIG. 3A shows a hydraulic control module 32a, 34a for
actuation of the hydro-mechanical actuator associated with a slat
20 that is a trailing edge flap. The trailing edge flap may include
an outboard slat 20d and an inboard slat 20c. The flap system 20'
may include a plurality of actuators 36g, 36h coupled to the
outboard slat 20d and a plurality of actuators 36e, 36f coupled to
the inboard slat 20c. The actuators may be rotary actuators. The
actuators 36e, 36f, 36g, 36h may each include an offset gearbox.
The trailing edge slat 20 may further include support bearings 41a,
41b and gearboxes 42a, 42b. A wing tip brake 43 may also be
provided along the outboard slat 20d. The outboard slat 20d and the
inboard slat 20c may also each include disconnect sensors 43a, 43b,
43c, 43d for disconnecting the control surfaces in the event of a
failure. The hydraulic control module 32a, 34a may include a
hydraulic power drive unit 32b connected to each of the inboard
slat 20c and the outboard slat 20d. The hydraulic power drive unit
32b may be secured to the aircraft 10.
[0036] FIG. 3B shows a traditional leading edge flap system 20''
that may implement the actuation system according to the present
invention. FIG. 3B shows a hydraulic control module 32a, 34a for
actuation of the hydro-mechanical actuator associated with a slat
20 that is a leading edge flap. The flap system 20'' may include an
outboard skew system 44 for detecting skew in an outboard slat 20d
and inboard skew sensors 45 for detecting skew in an inboard slat
20c. The flap system 20'' may include a plurality of actuators 36
and a torque shaft 46 coupled between the inboard slat 20c and the
outboard slat 20d. The actuators 36 may be rotary actuators. Each
actuator 36 may include a torque activated or load activated
overload brake 47. A driveline brake 48 may also be coupled to the
outboard slat 58. The flap system 20'' may include gearboxes 49a,
49b that are connected between the hydraulic power module 32a, 34a
and the inboard slat 20c. The hydraulic power module 32a, 34a may
include a hydraulic power drive unit 32b that is secured to the
aircraft 10.
[0037] Aspects of this application are directed to any number or
type of actuator assemblies 36, 38 that may be used in the aircraft
10. For example, the actuators may be rotary actuators or linear
actuators. Exemplary actuators 50a, 50b, 50c for use in accordance
with aspects of the present invention are illustrated in FIGS.
4A-4C. For purposes of simplicity, a single hydro-mechanical
actuator assembly is illustrated.
[0038] Referring to FIGS. 4A-4C, the hydro-mechanical actuator
assembly 50a, 50b, 50c may be variously disposed. The
hydro-mechanical actuator assembly 50a, 50b, 50c may be mounted
between a flap and the wing of the aircraft. The hydro-mechanical
actuator assembly may be mounted to other adjustable components
(e.g., elevators 12, rudder 14, ailerons 16, slats 20, and/or
spoilers 22) and structures (e.g., body of aircraft 10, wing 51,
tail, etc.). Each actuator assembly 50a, 50b, 50c may include a
motion control assembly 52 comprising a drive path 54 from the
motion control assembly 52 through the gears 53 to the component
(e.g., flap 18), which facilitates controlled movement of the
adjustable component. The motion control assembly 52 may include a
motion provider 56. The motion provider 56 may be a hydraulic motor
56-1 that is supplied with hydraulic fluid via the hydraulic
control module for driving an axial piston 56-2. The axial piston
56-2 may be connected to a drive shaft 56-3 via an associated
gearing assembly 56-4 for driving the drive shaft 56-3. Any
suitable gearing assembly may be used and the gearing assembly 56-4
may include any suitable gears, such as pinion gears.
[0039] The motion control assembly 52 may further include a screw
member 58 and a nut member 60. The motion control assembly 52 may
also include a suitable load or torque limiting device. As shown in
FIG. 4A, the load limiting device may be a slip clutch 64a that
limits the load by slipping, or an uncoupling means may be provided
that uncouples the load, such that overloads of the motion control
assembly 52 are prevented. As shown in FIGS. 4B and 4C, the load
limiting device may be a locking torque or load brake 64b, i.e. a
torque or load activated overload brake. As further shown in FIG.
4C, the motion provider 56 may further include a hydraulic brake
56-5. Other load limiting devices may be used.
[0040] The screw member 58 may be rotated by the motion control
assembly 52 and rotation of the screw member 58 may result in
linear movement of the nut member 60. Alternatively, (with
appropriate modifications), the nut member 60 may be rotated and
the screw member 58 moved linearly in response thereto. In either
or any event, the members 58/60 may incorporate low friction
elements (e.g., balls or rollers) therebetween (e.g., the screw
member 58 can be an Acme screw, ball screw, or a roller screw, for
example). Members 58/60 may also be sliding contact screws (e.g.,
buttress, square, etc.), or the actuator output may be a rotating
shaft that swings an arm through an arc, for example. The motion
control assembly 52 may be pivotally connected to the flight
control surface or to a self-aligning member that may be pivotally
connected to the flight control surface. In this manner, the screw
member 58 may be fixed from axial or translation movement relative
to the structure. The nut member 60 may be pivotally connected, via
a housing (not shown), to the self-aligning member that is
pivotally connected to the adjustable flight control surface (e.g.,
flap 18).
[0041] The motion control assembly 52 thus includes a drive path
from the motion provider 56 to the adjustable component (e.g., flap
18), with particular reference to the flaps illustrated in FIGS.
1-3B. The hydraulic motor's rotation of the screw member 58 in one
direction will pivot its leading edge upward, and the motor's
rotation of the screw member 58 in the opposite direction will
pivot its leading edge downward. The assembly 52 may also and/or
the motion provider 56 may incorporate "no back" features 70, 72 to
eliminate back-driving by aerodynamic forces, in compression 70
and/or in tension 72. A skewed roller and ratchet plate type device
is shown, however, other methods to provide irreversibility of the
actuator may be used in accordance with aspects of the present
invention. Such irreversibility may include but is not limited to
Acme Screw, Worm Gears, irreversible gearing, hydraulic valves, and
other such devices. Someone practiced in the art may apply this
control concept to systems where the motors operate under aiding
(regenerating) loads.
[0042] The motion provider 56 may not include rotational members
such as screw member 58 and the nut member 60. The rotary to linear
transducer (screw 58 and nut 60) may be a rolling or sliding
contact screw, a rotating shaft, or an arm that swings through an
arc. Thus, transferring movement to the component (e.g., flap 18).
However, relatively rotational members, and especially those
incorporating balls or rollers, often offer higher stiffness,
lighter weight, lower cost, and/or greater packaging flexibility.
During normal actuator operation, the assembly 52 will control
movement of the component (e.g., flap 18) through the drive
path.
[0043] The actuator assembly 50 may also include a retract stop 62.
The retract stop 62 may be coupled to the screw member 58 in such a
manner that the retract stop maintains stationary with respect to
the screw member. This provides a mechanism for re-synchronizing a
group of actuators periodically (e.g., after every retract cycle)
by driving into calibrated retract stop 62 at a controlled speed
and torque capability, for example.
[0044] Referring back to FIGS. 2A and 2B, the actuation system 30
is illustrated with respect to controlling the flaps 18 (e.g.,
inboard and outboard flaps of the aircraft 10). As illustrated in
FIGS. 2A and 2B, four discrete flaps 18a, 18b, 18c, 18d are shown.
Each flap may include redundant actuators (e.g., 36) and redundant
position sensors 40. As may be appreciated, the position sensors 40
are configured to sense the position of the component, and supply a
position signal representative thereof to the actuator controller.
The position sensor 40 may be implemented using any one of numerous
suitable position sensing devices including, for example, rotary
variable differential transformers (RVDTs), linear variable
differential transformers (LVDTs), potentiometers, various
resistive sensors, and optical sensors, just to name a few. In the
depicted embodiment, however, the position sensor 40 is implemented
using an LVDT.
[0045] The actuators 36 generally are responsible for actuating
movement of the adjustable component (e.g., flaps 18) with respect
to a stationary portion of the aircraft 10 (e.g. wing 51). Each
actuator 36 has a first end 66 coupled to a structure (e.g., body
of aircraft 10, wing 51, etc.) and a second end 68 coupled to the
component (e.g., flaps 18). The output of the actuators is
maintained near synchronous over the applied load range within the
volumetric difference between the motors over the operating range
between the no-load and the operating point.
[0046] Referring now to FIGS. 5A-F, exemplary configurations of the
hydraulic control modules 32a, 34a are shown. FIG. 5A is a
schematic drawings showing synchronous operation of the hydraulic
motors 56-1 within a tolerance of volumetric efficiency. Each motor
56-1 may include a retracting port 74, an extending port 76, and a
case drain port 78. The retracting port 74 of at least some of the
motors 56-1 may be in fluid communication with an extending port 76
of another motor 56-1 via a hydraulic line 80. At least one of the
motors 56-1 may include a retracting port 74 that is not in fluid
communication with an extending port 76 of another motor 56-1 and
may be in fluid communication with a fluid source 32c of the
hydraulic control module 32a, 34a via a hydraulic line 82. At least
one of the motors 56-1 may include an extending port 76 or a fluid
supply side of the motor 56-1 that is not in fluid communication
with a retracting port 74 of another motor 56-1 and may be in fluid
communication with the fluid source of the hydraulic control module
32a, 34a via a hydraulic line 84. Each drain port 78 may be in
fluid communication with the fluid source 32c of the hydraulic
control module 32a, 34a via a hydraulic line 86. The configuration
of the hydraulic system may enable the flow through each hydraulic
motor 56-1 to be the same. The gear ratio in each motion provider
may also be adjusted to vary the leakage through each motor, such
that the internal leakage of each motor is well-defined.
[0047] Referring in addition to FIG. 5B, each hydraulic motor 56-1
may include a directional control valve, such as a by-pass valve 86
connected between the hydraulic lines 80 of the retracting ports 74
and the extending ports 76. The by-pass valve 86 may be any
suitable type of valve, such as a fine adjust solenoid valve.
During operation, the by-pass valve 86 may be moveable between a
closed position 86a or an open position 86b that enables fluid flow
through the valve 86. The by-pass valve 86 may be normally in the
closed position 86a such that fluid is supplied to the extending
port 76 of the corresponding motor 56-1. When the by-pass valve 86
is in the open position 86b, as shown in FIG. 5B, fluid flowing
from the retracting port 74 of one of the motors 56-1 may by-pass
the extending port 76 of an adjacent motor 56-1 and flow to the
hydraulic line 80 of the retracting port 74 of the adjacent motor
56-1. The by-pass valve 86 may be briefly opened for any leading
actuator. Using the by-pass valve 86 may enable the lead actuator
to slow down and allow the remaining actuators to catch up such
that the group of actuators are synchronized. Any suitable number
of by-pass valves may be used.
[0048] Referring in addition to FIGS. 5C-F, the actuation system 30
may include a pilot-operated load limiting valve 88, or shut-off
valve, for each actuator, in addition to the directional control
valve. The pilot-operated load limiting valves 88 may be arranged
along the hydraulic fluid lines 80 and may block flow to one of the
actuators when supply pressure exceeds a predetermined value. Each
load limiting valve 88 may be moveable between a closed position
88a and an open position 88b. During operation of the actuators,
when pressure in the supply side or the extending port 76 of a
corresponding actuator rises to a predetermined level, the pilot
chamber of the load limiting valve 88 may drive the valve 88
towards the closed position 88a, such that fluid flow through the
hydraulic line 80 to the extending port 76 is blocked. The load
limiting valves 88 may be used to prevent overload of the actuators
and any suitable number of load limiting valves 88 may be used.
Each load limiting valve 88 may have a predetermined setting that
is unique for each valve 88. As further shown in FIG. 5D, the load
limiting valves 88 may be configured such that during an actuator
overload, the delta pressure across the motor 56-1 may increase and
causes the pilot chamber of the valve 88 to drive the valve 88
towards the closed position 88a. As shown in FIG. 5E, the
load-limiting valves 88 may be configured as bi-directional valves
to accommodate for overloading on either side of the motor
56-1.
[0049] As shown in FIG. 5F, in lieu of directional valves 86 and
load limiting valves 88, the hydraulic control module 32a, 34a may
include a plurality of electro-hydraulic servo valves 90 that are
associated with the actuators for providing open loop or servo
control of the actuation system 30, such that the hydraulic flow
rate is controlled to assure that the motors operate at a
predetermined speed. The hydraulic control module 32a, 34a may
include central control electronics 32d and each electro-hydraulic
servo valve 90 may be in electronic communication with the central
control electronics 32d for controlling operation of the valves
90.
[0050] Referring now to FIG. 6, a schematic drawing of the
operation of the hydraulic control module 32a, 34a is shown. As
aforementioned, the hydraulic control module 32a, 34a may include
any suitable numbers or types of control valves for controlling the
flow of hydraulic fluid to the actuators. FIG. 6 shows the
direction of fluid flow through the actuation system. The hydraulic
control module 32a, 34a, may include a motor operated valve 92 that
may be in fluid communication with a fluid source 94 for supplying
hydraulic fluid to the actuation system. The motor operated valve
92 may be in communication with an arming valve 95. When the arming
valve 95 is actuated or in the open position allowing fluid to pass
therethrough, the hydraulic fluid may flow to the directional
control valve, i.e. bypass flow valve 86. The hydraulic control
module 32a, 34a may further include a plurality of pressure
compensated flow control valves 96a, 96b that each maintain a set
pressure differential. The control valves 96a, 96b may include a
first control valve 96a that compensates for flow on a left or
right side of the corresponding actuator and a second control valve
96b that compensates for flow on the other of the left or right
side of the actuator. The hydraulic control module 32a, 34a may
include a plurality of directional control valves 86 and each
directional control valve 86 may correspond to one of the plurality
of actuators. Each directional control valve 86 may also be in
communication with both a right side pressure compensated flow
control valve 96b and a left side pressure compensated flow control
valve 96a.
[0051] Referring now to FIG. 7, illustrated is a flow chart 200
describing the steps of an exemplary method of synchronizing
different motors and/or actuator assemblies 36, 38 powered by a
hydraulic control module and assigned to a common group (e.g., the
same or related flight surfaces) in accordance with the present
invention. Beginning at block 202, the position of each actuator
assembly 36, 38 of the group is determined, for example, using
position sensors 40. More particularly, data from each position
sensor 40 of a group is used to determine a position for the
actuator assembly corresponding to that sensor 40. For example, in
the case where the position sensor 40 is an LVDT, the voltage
output by the LVDT is proportional to position of the actuator
assembly along its range of motion. Thus, based on the voltage
output by the LVDT the position of the actuator assembly along its
range of motion can be determined.
[0052] Next at block 204, the position data obtained at block 202
for each actuator assembly of the group is compared to one another.
Such comparison may be by way of simply comparing the voltage
provided by each LVDT 40, for example.
[0053] At block 206 it is determined if position correction is
required. In this regard, if the position of each actuator assembly
36, 38 in the group is within a prescribed tolerance of the other
actuator assemblies 36, 38 of the group (e.g., within 2 percent),
then no correction is required and the method moves to block 208
where full hydraulic power is provided to all the actuator
assemblies of the group. The method then moves back to block 202
and repeats.
[0054] Moving back to block 206, if the position of one or more
actuator assemblies 36, 38 is not within a prescribed tolerance of
the position of other actuator assemblies 36, 38 of the group, then
the method moves to block 210 where it is determined which of the
actuator assemblies 36, 38 positionally leads the other actuator
assemblies. In this regard, the position data provided by the
position sensor 40 can be used to determine which of the actuator
assemblies positionally leads the other actuator assemblies.
[0055] For example, if 0 volts represents a fully retracted
position of the flight surface and 10 volts represents a fully
extended position of the flight surface, then as the actuator
assembly 36, 38 moves the flight surface toward the fully extended
position the voltage provided by the position sensor 40 will
increase. The voltage from each position sensor 40 of the group
then can be compared to determine which sensor 40 is indicating the
highest voltage. The actuator assembly 36, 38 associated with the
sensor providing the highest voltage then can be said to be the
leading actuator. Conversely, if the actuator assembly 36, 38 moves
the flight surface toward the fully retracted position the voltage
provided by the position sensor will decrease. The actuator
assembly associated the sensor providing the lowest voltage then
can be said to be the leading actuator assembly.
[0056] Upon identifying the lead actuator assembly, the method
moves to block 212 where the power provided to a motion provider of
the lead actuator assembly is reduced. In this regard, the
hydraulic control module may be commanded to reduce the power
provided to the motion provider of the lead actuator assembly. Such
power reduction causes the motion provider for the lead actuator
assembly 36, 38 to slow down, thereby allowing the other actuator
assemblies to positionally catch up to the lead actuator assembly.
The method then moves back to block 202 and repeats.
[0057] In determining which actuator assembly 36, 38 positionally
leads the other actuator assemblies, it is possible that more than
one actuator assembly 36, 38 is found to positionally lead the
other actuators. In such event, one actuator assembly (a first
actuator assembly) may have a greater lead than the other actuator
assembly (a second actuator assembly), and therefore, the first
actuator assembly 36, 38 may be identified as the lead actuator
assembly. Therefore, the method may reduce power only to the motion
provider of the first actuator assembly 36, 38 while retaining full
power to the motion providers of other actuator assemblies
(including the second actuator assembly). Eventually, however, the
position error for the first actuator assembly will be reduced to
the point where it no longer leads the second actuator assembly. At
this time, the method will automatically restore power to the
motion provider of the first actuator assembly and reduce power to
the motion provider of the second actuator assembly. In this
manner, the two leading actuator assemblies will be alternately
stepped back in line with the position of the other actuator
assemblies.
[0058] It is possible that two or more actuator assemblies 36, 38
positionally lead one or more other actuator assemblies by the same
distance. In this instance, power to the motion providers for the
two or more actuator assemblies may be reduced such that both
actuator assemblies slow down relative to the one or more lagging
actuator assemblies.
[0059] Referring now to FIG. 8, schematically shown is an exemplary
controller 32, 34 (as also shown in FIGS. 2A and 2B) that may be
used to execute the method of FIG. 7. The controller or controllers
32, 34 may be in communication with the hydraulic control modules
for controlling the actuation system. The controller 32, 34
includes a control circuit 250 that is responsible for overall
operation of the controller 32, 34. For this purpose, the control
circuit 250 includes a processor 252 that executes various
applications, such as a position control function that carries out
tasks that enable fine position control of the actuator assemblies
as described herein. The position control function may be
implemented in the form of logical instructions that are executed
by the processor.
[0060] The processor 252 of the control circuit 250 may be a
central processing unit (CPU), microcontroller or microprocessor.
The processor 252 executes code stored in a memory (not shown)
within the control circuit 250 and/or in a separate memory, such as
a memory 254. The memory 254 may be, for example, one or more of a
buffer, a flash memory, a hard drive, a removable media, a volatile
memory, a non-volatile memory, a random access memory (RAM), or
other suitable device. In a typical arrangement, the memory 254
includes a non-volatile memory for long term data storage and a
volatile memory that functions as system memory for the control
circuit 250. The memory 254 may exchange data with the control
circuit 250 over a data bus. Accompanying control lines and an
address bus between the memory 254 and the control circuit 250 also
may be present. The memory 254 is considered a non-transitory
computer readable medium.
[0061] The controller 132, 134 may further include one or more
input/output (I/O) interface(s) 256. The I/O interface(s) 256 may
be in the form of typical I/O interfaces and may include one or
more electrical connectors for operatively connecting the
controller 32, 34 to another device (e.g., a computer) via a cable
and/or to received and output signals (e.g., digital or analog
I/O). Further, operating power may be received over the I/O
interface(s) 256 and power to charge a battery of a power supply
unit (PSU) 258 within the controller 32, 34 may be received over
the I/O interface(s) 256. The PSU 258 may supply power to operate
the controller 32, 34 in the absence of an external power
source.
[0062] Although the invention has been shown and described with
respect to a certain embodiment or embodiments, it is obvious that
equivalent alterations and modifications will occur to others
skilled in the art upon the reading and understanding of this
specification and the annexed drawings. In particular regard to the
various functions performed by the above described elements
(components, assemblies, devices, compositions, etc.), the terms
(including a reference to a "means") used to describe such elements
are intended to correspond, unless otherwise indicated, to any
element which performs the specified function of the described
element (i.e., that is functionally equivalent), even though not
structurally equivalent to the disclosed structure which performs
the function in the herein illustrated exemplary embodiment or
embodiments of the invention. In addition, while a particular
feature of the invention may have been described above with respect
to only one or more of several illustrated embodiments, such
feature may be combined with one or more other features of the
other embodiments, as may be desired and advantageous for any given
or particular application.
* * * * *